Known in the art is a method of preparing 1-butene or hexenes (SU, A, 65B119) by dimerization of ethylene or co-dimerization of etylene and propylene in the presence of the catalyst consisting of titanium alcoholate of the formula Ti(OR).sub.4 and a complex organoaluminium compound of the formula AlR.sub.3 L, where L is an alkyl radical having from 1 to 4 carbon atoms and L is a compound selected from the group dialkyl ether, dialkylamine, aliphatic diamine, di(diphenylphosphino) ethylamine, and diethylsulphide. The interaction of monomers is performed in an organic solvent at a temperature of 0.degree.-80.degree. C. under pressure 0.1-20.0 MPa. The known method is characterized by a low yield of the final product (up to 390 g/g Ti(OR).sub.4) and by the formation of a solid polymer (up to 0.1 mass %) in the reaction zone. Also known in the art is a method of preparing 1-butene (SU, A, 459451) residing in dimerization of ethylene in the presence of a complex organometallic catalyst consisting of tetraalkoxytitanate, trialkylaluminium (Alk=C.sub. 1 -C.sub.4) and an organic additive: isopropanol, butanol, or phenol, in an organic solvent at a temperature of from 70.degree. to 80.degree. C. under pressure from 0.25 to 1.4 MPa.
The process is highly selective (99.75 vol. % of 1-butene) but the yield of 1-butene is low (101-214 g/g Ti(OR).sub.1 per hour).
Likewise known in the art is a method of preparing 1-butene and/or hexenes U.S. Pat. No. 4,101,600) residing in dimerization of ethylene and/or co-dimerization of ethylene and propylene in the presence of a complex organometallic catalyst containing titanium alcoholate of the formula Ti(OR.sup.1).sub.4, where R.sup.1 is an alkyl radical having from 1 to 8 carbon atoms or aryl, trialkylaluminium of the formula AlR.sup.2.sub.3, where R.sup.2 is an alkyl radical having from 1 to 6 carbon atoms, at a temperature of from 0.degree. to 100.degree. C. under enhanced pressure in an organic solvent. To increase the activity and selectivity of the catalyst, it is pre-treated with an ethylene-hydrogen mixture. The mixture is, however, dangerously explosive which complicates the technological process and requires a special equipment. The yield of 1-butene is low and amounts only to 80-347 g/g Ti(OR.sup.1).sub.4 per hour, although the content of hexenes in the firnal product attains 25 mass % in the presence of solid polymer in amount to 0.4 mass %.